Intersection Points & Finding Unknown Variable

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SUMMARY

The discussion focuses on the conditions under which the line represented by the equation y = x + k intersects the parabola defined by y = x^2 + x - 2 at two distinct points. The key conclusion is that the intersection occurs when k > -2, allowing for real solutions for x. The discriminant method is utilized to analyze the quadratic equation formed by setting the two equations equal, leading to the determination of valid k values: k < -2 results in no real intersections, while k = -2 yields a single intersection point.

PREREQUISITES
  • Understanding of quadratic equations and their properties
  • Familiarity with the discriminant method in algebra
  • Knowledge of linear equations and their graphical representations
  • Basic skills in manipulating algebraic expressions
NEXT STEPS
  • Study the discriminant and its role in determining the nature of roots in quadratic equations
  • Explore the graphical representation of parabolas and lines to visualize intersection points
  • Learn about the implications of different values of k in linear equations
  • Investigate the concept of breakpoints in piecewise functions
USEFUL FOR

Students and educators in mathematics, particularly those focusing on algebra and quadratic functions, as well as anyone interested in understanding the intersection of linear and quadratic equations.

confusedatmath
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The line with equation y = x + k, where k is a real number, intersects the parabola with equation y = x^2 + x − 2 in two distinct points if

I first made the equations equal each other

x + k = x^2 + x − 2
0 = x^2 -2 -k

From here i thought you use the discriminate a=1 b=o c=-2-k

but this isn't right, because the answer to choose from

k < − 2

k > − 2

k = − 2

k < 2

k ≠ 2
 
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confusedatmath said:
The line with equation y = x + k, where k is a real number, intersects the parabola with equation y = + x − 2 in two distinct points if

I first made the equations equal each other

x + k = + x − 2
0 = -2 -k

From here i thought you use the discriminate a=1 b=o c=-2-k

but this isn't right, because the answer to choose from

k < − 2

k > − 2

k = − 2

k < 2

k ≠ 2

Hello.

Check the wording of the question. The parable, need that 'x' is not high to the power 1. (would be a straight line)

Regards.
 
mente oscura said:
Hello.

Check the wording of the question. The parable, need that 'x' is not high to the power 1. (would be a straight line)

Regards.
i fixed it :p read again, it was a mistake i forgot the x^2
 
confusedatmath said:
The line with equation y = x + k, where k is a real number, intersects the parabola with equation y = x^2 + x − 2 in two distinct points if

I first made the equations equal each other

x + k = x^2 + x − 2
0 = x^2 -2 -k

From here i thought you use the discriminate a=1 b=o c=-2-k

but this isn't right, because the answer to choose from

k < − 2

k > − 2

k = − 2

k < 2

k ≠ 2

Now yes.

0=x^2-2-k

x^2=k+2

x=\pm{} \sqrt{k+2}

1º) k&lt;-2 \rightarrow{}x \cancel{\in}{R}

2º) k&gt;-2 \rightarrow{}x \in{R}

3º) k=-2 \rightarrow{}x=0, only a breakpoint.

Regards.
 

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